Security deposit accounting and interest
Enter the deposit, the dates, the annual rate from your lease or local rule, and the deductions. The page figures the interest earned, totals the deductions, and shows the amount to return to the tenant or the balance the tenant owes, as an itemized statement with every total checked a second way.
Your numbers stay on this device. Nothing is uploaded.
The rate is the one you enter; this page does not supply one. What selected state statutes say about deposits, with sources, is in the security deposit rules by state lookup.
Interest already paid or credited
With interest compounded annually, a dated payment leaves the compounding balance on its date and earns nothing after that; a year that holds a payment is split at that date. A payment with no date cannot be placed, so it stays in the balance and a warning says so. Simple interest is always figured on the deposit alone.
| Date | Amount |
|---|
Deductions
| Description | Amount |
|---|
Compare with an existing statement (optional)
Deposit statement
What gets checked
- Interest is calculated twice, in two different orders of operations, and the two results match to the cent.
- Days held are counted two independent ways, and the interest periods cover every day with no gap or overlap.
- Deposit plus interest earned, minus interest already paid, minus deductions equals the balance, confirmed by a second pass over every line.
- The move-out date is after the date the deposit was received, and no deduction or interest payment is negative.
- If you enter figures from a statement prepared elsewhere, they are compared with the calculated interest and balance.
- Warnings (not failures): deductions larger than the deposit plus interest, interest paid above interest earned, payments dated outside the tenancy, and, when compounding, payments with no date (they could not be taken out of the compounding balance).
How it works
- Enter the deposit and dates. Type the tenant, the property, the deposit amount, the date it was received, and the move-out date.
- Enter the rate and method. Type the annual interest rate as a percent (0 is allowed) and pick simple interest or interest compounded annually. The rate is yours to enter; the page does not supply one.
- List interest already paid and deductions. Add any interest already paid or credited to the tenant, then each deduction with its description and amount.
- Review, print, or export. The itemized statement shows interest by period, the deductions, and the amount to return or the balance owed, with the checks underneath. Print it or download Excel or CSV.
Worked example
A $1,800.00 deposit received 2023-03-01, move-out 2025-06-30 (852 days), at 2% simple interest on actual days / 365, with $36.00 of interest already paid and three deductions.
| Line | Amount |
|---|---|
| Deposit received | $1,800.00 |
| Interest earned | $84.03 |
| Interest already paid | -$36.00 |
| Deduction: Carpet cleaning | -$185.00 |
| Deduction: Wall repair and paint | -$240.00 |
| Deduction: Unpaid water bill | -$62.47 |
| Amount to return to tenant | $1,360.56 |
Interest is $1,800.00 x 2% x 852 / 365 = $84.03 after rounding to the cent. Deductions total $487.47, and $1,800.00 + $84.03 - $36.00 - $487.47 = $1,360.56.
The example uses made-up names and numbers.
Questions
How is the interest calculated?
Simple interest is the deposit times the annual rate times the actual number of days held, divided by 365, rounded once to the nearest cent with halves rounded up. Compounded annually adds a full year's interest to the balance on each anniversary of the date received, rounded to the cent each time, then applies simple interest for the days after the last anniversary. Interest that was already paid out has left the balance: a dated payment lowers the compounding balance by its amount from that date, a payment on an anniversary is taken out after that year's interest is added, and a year that holds a payment is split at the payment date with each part earning balance times rate times its days over the days in that year, rounded to the cent. So $1,000.00 at 5% compounded annually for two years with $50.00 paid at the end of year one earns $50.00 + $50.00 = $100.00, not $102.50. Both calculation paths apply this rule separately and have to agree.
What rate does it use?
Only the rate you type. The page does not choose a rate and does not say which rate, method, or deductions apply to a tenancy. The state lookup linked on this page shows what selected statutes say, with their sources.
What happens when deductions are more than the deposit?
The statement switches to show a balance the tenant owes instead of an amount to return, and the checks show a warning so the change is easy to notice. The arithmetic checks still apply.
How are days counted?
Actual calendar days from the date received to the move-out date. The date received is day zero and the move-out date is the last day counted, so 1 January to 31 January is 30 days. Leap days count as days.
Is anything uploaded?
No. The figures are kept in this browser on your device and are never sent to a server.
This tool calculates and checks numbers. It is not legal, tax, or medical advice.